The inventive concept relates to a CMOS image sensor.
Image sensors are semiconductor devices capable of converting optical images into electric signals. Such image sensors may be classified into various types, including charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) types of image sensors. A CMOS image sensor (CIS) includes a two-dimensional array of pixels. Each of the pixels includes a photodiode (PD), which converts incident light into an electric signal.